1. Field of the Invention
The present invention relates to an improvement on a cartridge chamber lid opening-and-closing mechanism.
2. Description of Related Art
In recent years, there have been put on the market, cameras having the structure in which when a film cartridge of the type having even a fore end part (leader part) of film rolled therein has been loaded into the camera, a fork of the camera is driven to thrust out the film from the inside of the film cartridge and the film is advanced to be wound onto a spool shaft of the camera.
Such a kind of camera has a shortcoming in that, when the film has been pulled out from the inside of the film cartridge loaded in a cartridge chamber of the camera, the film would be exposed to light if a cartridge chamber lid happens to be inadvertently opened by the user of the camera. To prevent this accident, a lock mechanism for the cartridge chamber lid has been variously developed. For example, in Japanese Laid-Open Patent Application No. HEI 8-286245, there is disclosed a camera in which a lock member, which is disposed at a part of a film transport gear train, is arranged to render a cartridge chamber lid inoperable during process of winding or rewinding the film by moving the lock member to a position where the lock member acts to inhibit an opening operation on an operation knob provided at the cartridge chamber lid.
According to the camera disclosed in Japanese Laid-Open Patent Application No. HEI 8-286245, the cartridge chamber lid can be prevented from being inadvertently opened at the time of winding or rewinding the film since the operation knob provided for operating the cartridge chamber lid is locked by the lock member under that condition. However, during the time when the rotating direction of a film transport motor is being changed from the winding direction to the rewinding direction upon completion of photo-taking of the last frame or upon the turning-on of a forced rewinding switch, the lock member is brought into a position where the operation knob is left unlocked. Therefore, if the operation knob happens to be inadvertently operated under this condition, the cartridge chamber lid would accidentally open.
In accordance with one aspect of the invention, there is provided an optical apparatus having a cartridge chamber lid, which comprises a driving gear arranged to drive a member which engages a spool of a cartridge, and a lock mechanism which unlocks the cartridge chamber lid when a rotating direction of the driving gear changes from a first rotating direction for rewinding a film to a second rotating direction for thrusting out the film and which maintains locking the cartridge chamber lid when the rotating direction of the driving gear changes from the second rotating direction to the first rotating direction, so that the cartridge chamber lid can be locked and unlocked at an apposite timing.
The above and other aspects and features of the invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings.